Note: Descriptions are shown in the official language in which they were submitted.
Z~2~92l.
DISHWASHER FILTER ARRANGEMENT
BACKGROUND OF THE INVENTION
Dishwashers have a washing chamber including side
walls, a top wall and a bottom wall, and a water
circulation system mounted in the bottom wall of the
5 washing chamber. The circulation system pumps water
upwardly through a rotating wash arm for spraying water
onto the dishes and other objects to be cleaned within
the washing chamber. Typically, the water sprayed from
the wash arm collects in the bottom of the washing
chamber and is strained so as to remove large food
particles from the water. The strained water is then
recirculated by the circulation system for further
spraying of the dishes.
A problem associated with conventional dishwasher
circulation systems is that smaller food particles pass
through the strainer, and thus through the circulation
system. These smaller food particles recirculate in the
circulation system and tend to become redeposited on the
dishes and other articles being washed.
SUMMARY OF THE INVENTION
An objective of the present invention is an improved
water circulation system for dishwashers.
Another objective of the present invention is the
25 provision of a water circulation system for dishwashers
having a filter for removing some of the small food
particles from the wash water prior to recirculation of
the water into the washing chamber.
A further objective of the present invention is the
30 provision of a water circulation system for dishwashers
having both a strainer portion and a filter portion.
Still another objective of the present invention is
the provision of a dishwasher filter arrangement which
ZlZ89Zl.
filters wash water fed from the wash arm and which is
backwashed during the washing cycle.
Yet another objective of the present invention is
the provision of a dishwasher filter arrangement having a
collection chamber for collecting small food particles
5 and for disposing of the small food particles after the
washing cycle is completed.
Another objective of the present invention is the
provision of an improved combination strainer and filter
apparatus for a dishwasher which allows simple model
o differentiation during manufacturing and which can be
retrofit to existing dishwashers.
A further objective of the present invention is the
provision of a method of circulating wash water in a
dishwasher wherein a first portion of the wash water is
15 strained to remove large food particles therefrom, and a
second portion of the wash water is filtered to remove
smaller food particles therefrom, prior to recirculation
of the wash water back to the washing chamber.
The water circulation system of the present
20 invention is an improvement over existing circulation
systems in dishwashers. The water circulation system is
included in a dishwasher having a washing chamber, a pump
housing and a pump within the pump housing for supplying
wash water to the washing chamber to clean objects
25 therein. A strainer is provided for straining large
objects from the wash water and defines a first water
recycling inlet into the pump housing for recirculation
of wash water to the washing chamber by the pump. The
water circulation system also includes a filter for
30 filtering food particles from the wash water and defining
a second water recycling inlet into the pump housing for
recirculation of wash water to the washing chamber by the
pump. A collection chamber is positioned adjacent the
2128921
filter to collect food particles filtered from the wash
water. A cylindrical member has a side wall and a
bottom wall between the strainer and the filter. The
cylindrical member defines the collection chamber.
BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS
Figure 1 is a perspective view showing the front
door of a dishwasher in a closed position.
Figure 2 is a view similar to Figure 1 showing the
dishwasher door in an open position.
o Figure 3 is a sectional view taken along lines 3-3
of Figure 2.
Figure 4 is a sectional view taken along lines 4-4
of Figure 3.
Figure 5 is a sectional view taken along lines 5-5
s of Figure 4.
Figure 6 is a sectional view taken along lines 6-6
of Figure 5.
Figure 7 is an enlarged partial sectional view
taken along lines 7-7 of Figure 6, and showing the
closure flap in a closed position.
Figure 8 is a view similar to Figure 7 showing the
closure flap in an open position.
Figure 9 is a partial perspective view
illustrating the backwash system for the filter
element.
Figure 10 is a partial perspective view showing
the actuator arm for the closure flap.
Figure 11 is a fragmentary sectional view taken
generally along lines 11-11 of Figure 6.
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENT
With reference to the drawings, a dishwasher 10 is
shown in Figures 1 and 2. The dishwasher includes a
A
2128921
door 12 pivotally movable between the closed position
shown in Figure 1 and the open position shown in Figure
2. The dishwasher 10 further includes sidewalls 14, a
bottom
3a
2~Z~92~.
wall 16, and a top wall 18 which together define a
washing chamber 20. An upper rack 22 is provided within
the washing chamber 20, and a lower rack is typically
provided, but is not shown in Figure 2 for purposes of
clarity. The above-described structure of the dishwasher
5 lO iS conventional, and does not form a part of the
present invention.
The present invention is directed towards a water
circulation and filtration system 24 which is mounted in
the bottom wall 16 of the dishwasher 10. The details of
the circulation system 24 are shown in Figure 3-10.
More particularly, the water circulation and
filtration system 24 includes a pump housing 26, a pump
28 mounted within the housing 26, and a motor 30
operatively connected to the pump 28.
The pump 28 provides wash water to a pump volute 32.
A wash arm support 34 is rotatably mounted upon the
volute 32. An elongated wash arm 36 is mounted on the
wash arm support 34 for rotation therewith and is secured
with a spray nozzle 38 received on the wash arm support
20 34. A jump up nozzle (not shown) is operatively mounted
within the spray nozzle 38. The wash arm 36 includes an
upper surface 40 having a plurality of spray apertures 42
extending along the length of the wash arm 36. As best
shown in Figures 5 and 7, the wash arm 36 also includes a
25 lower surface 44 with a single aperture 46 therein.
The pump housing 26 has an open upper end 48 which
is covered with an annular filter assembly 50. The
filter assembly 50 includes a strainer portion 52
extending around the parameter edge of the assembly. The
30 strainer portion 52 includes a plurality of openings 54
through which wash water from the washing chamber 20 may
pass into the pump housing 26 for recirculation by the
pump 28 through the volute 32, arm support 34, and wash
arm 36 and back into the washing chamber 20. The
2~Z~3921
strainer portion 52 keeps large objects including
silverware from passing therethrough into the pump
housing 26.
An upstanding cylindrical wall 56 and a bottom wall
58 are spaced radially inwardly from the strainer portion
5 52, and surround the wash arm support 34. The
cylindrical wall 56 and the bottom wall 58 define a
collection chamber 60 for collecting food particles, as
described below. An annular filter element 61 is
received within a slot 62 in the bottom wall 58. An
o annular cap 64 having a downwardly sloped upper surface
66 snap fits onto the wall 56 so as to cover the filter
element 61. The perimeter edge of the cap 64 is spaced
apart from the cylindrical wall 56 so that wash water and
food debris directed through aperture 46 as well as wash
15 and food debris dropping onto the cap 64 from within
washing chamber 20 will flow down the sloped surface 66
into the collection chamber 60. The filter element 61
has a plurality of fine apertures which allow wash water
collected within the collection chamber 60 to pass
20 therethrough while the food particles are retained in the
collection chamber 60. Thus, the wash water in the
collection chamber 60 is filtered by the filter element
61 before passing into the pump housing 26 for further
circulation through the pump volute 32, the wash arm
25 support 34 and the wash arm 36 back into the washing
chamber 20 for cleaning the dishes therein.
As best shown in Figures 6 and 11, the bottom wall
58 includes a first ramped or sloped portion 68 which
extends steeply downward in a clockwise direction from
30 the high point 69 of the bottom wall 58 to a discharge
opening 70. The bottom wall 58 also includes a second
ramped or sloped portion 71 which extends downwardly in a
counterclockwise direction for an angular distance of
approximately 270 degrees from the high point 69 of the
2~Z892~
bottom wall 58 to the discharge opening 70. In this
distance, the second sloped portion 71 slopes downwardly
approximately three-eighths of an inch from the high
point 69. The area of the collection chamber 60 defined
by the first sloped portion 68 captures the majority of
5 the food debris adjacent the opening 70.
A closure flap 72 is pivotally mounted about an axis
74 within the pump housing 26 for movement between a
closed position sealing discharge opening 70, as shown in
Figure 7, and an open position spaced apart from the
discharge opening 70, as seen in Figure 8. The end of
the closure flap 72 located in juxtaposition to the
discharge opening includes a cone shaped protrusion 73.
The protrusion 73 extends through the opening 70 and
upwardly into the food debris captured in the vicinity of
15 opening 70. As the closure flap 72 is opened, as shown
in Figure 8, the protrusion 73 will tend to start the
flow of food from the collection chamber 60 by creating
an opening in the debris or loosening any compaction
around the discharge opening 70. The movement of the
20 closure flap 72 is controlled by a lever arm 76 which is
actuated by a solenoid 78 operatively connected to
controls (not shown) of the dishwasher 10. As best shown
in Figure 6, spring 80 extends between attachment point
81 on the closure flap 72 and attachment point 83 which
25 extends downwardly from the bottom wall 58 and normally
biases the closure flap 72 to the closed position.
The bottom wall 58 of the collection chamber 60
includes a flush port 82. The pump housing 26 includes a
water discharge line 84, with an upstanding pipe 86
30 extending upwardly therefrom. The pipe 86 is aligned
beneath the flush port 82 such that when the pump housing
26 is drained at the end of the washing cycle of the
dishwasher, a ~uantity of wash water is forced upwardly
through the pipe 86 and the flush port 82 for flushing
2128921.
the collection chamber 60 including the first and second
portions 68 and 71, thereby removing all of the collected
food particles through the discharge opening 70.
The wash arm support 34 includes a small aperture
88, as best seen in Figure 5 and 9. The aperture 88 is
s elongated an angled with respect to the longitudinal axis
of the support 34. The opposite ends of the aperture 88
are chamfered. The aperture 88 provides an expanding
spray or jet of water, as represented by arrows 90 in
Figure 9, which continuously backwashes the filter
o element 61 when water is pumped through the wash arm
support 34. Since the wash arm support 34 rotates while
water is being pumped therethrough, the aperture 88
directs the spray of water 90 along the entire inner
surface of the filter element 61 to remove small food
15 particles from the apertures in the filter element 61, so
as to prevent clogging of the filter element 61.
In operation, water is supplied to the washing
chamber 20, and flows through the filter assembly 50 to
the pump 28. The pump 28 forces the water upwardly
20 through the volute 32, the wash arm support 34, and the
wash arm 36. The water is sprayed from the wash arm 36
through the spray apertures 42 on the upper surface 40 of
the wash arm 36, and through the spray nozzle 38 and jump
up nozzle (not shown) for cleaning dishes and other
25 objects contained within the washing chamber 20. The
wash arm support 34 and wash arm 36 rotate when water is
ejected therefrom due to the shape and location of the
spray apertures 42. A quantity of the recirculating wash
water is directed through the bottom aperture 46 on the
30 lower surface 44 of the wash arm 36 for continuously
providing a portion of the wash water to be deposited on
the sloped upper surface 66 of the annular cap 64.
Approximately 1/13 of the water recirculated through the
2~28921.
wash system is directed through the lower aperture 46
onto the sloped surface 66.
As the initial quantity of water from the pump 28 is
sprayed from the wash arm 36 and nozzles 38, the water
impinges upon the dishes and other objects to remove food
5 particles therefrom. A first portion of the water flows
through the bottom aperture 46 on the lower surface 44 of
the wash arm 36 and is directed onto the cap 64 and flows
down the sloped surface 66 thereof into the collection
chamber 60. The water filters through the filter element
61 so as to remove food particles therefrom. The water
then passes into the pump housing 26 and through a
chopper 92 and chopper plate 94 into the pump 28, for
further circulation to the washing chamber 20. In
addition to directing wash water and food particles
15 toward collection chamber 60, the flow through aperture
46 will provide a cleaning and flushing action of sloped
surface 66.
A second portion of the wash water collects in the
bottom of the washing chamber 20 and passes through the
20 strainer portion 52 of the filter assembly 50, thereby
removing large objects from the wash water. The strained
wash water passes into the pump housing 26, and through
the chopper 92 and chopper plate 94 into the pump 28, for
further circulation to the washing chamber 20. The
25 chopper 92 cuts up any food particles which pass through
the strainer portion 52.
With the water circulation and filtration system 24,
the water is repeatedly filtered as it recirculates
through the pump 28 for the sequential wash and rinse
30 cycles of the dishwasher 10. During the first wash
cycle, large particles in the water are removed by the
strainer portion 52, while smaller particles pass through
the strainer portion. The water with small particles is
pumped by the pump 28 back through the wash arm 36 for
Z~289Zl.
ejection through apertures 42 and 46. The water with
small particles which flows down the sloped cap 64 is
filtered by the filter element 61 to remove the small
particles. This process continues, such that the
recirculating water becomes progressively cleaner as
s large particles are removed by the strainer portion 52
and small particles are removed by the filter element 61.
At the completion of the wash cycle, the solenoid 78
is actuated so as to raise the lever arm 76, which
engages the rearward end of the closure flap 72, as seen
in Figure 8. The closure flap 72 thus pivots about the
axis 74 so as to be disengaged from the discharge opening
70 in the bottom wall 58 of the collection chamber 60.
At the same time that the solenoid 78 is actuated, wash
water within the pump housing 26 is being drained through
the discharge line 84. As water passes through the
discharge line 84, a quantity thereof is forced upwardly
through the pipe 86 and through the flush port 82 in the
bottom wall 58 of the collection chamber 60, thereby
flushing food particles from the collection chamber 60
20 for discharge through the opening 70 into the pump
housing 26 for drainage from the circulation system.
An advantage of the present dishwasher filter
arrangement is that the filter assembly 50 including the
strainer portion 52, the collection chamber 60, flap 72
25 and annular cap 64 is an integral assembly completely
separate from the pump 28. The filter assembly 50 can
thus be assembled at a remote, off-assembly line,
location and then brought to the assembly line for
attachment to the pump 28. This separate integral filter
30 assembly 50 allows simple model differentiation on the
assembly line. For example, dishwashers having either
large object straining and small particle filtering as
with filter assembly 50 or having only a strainer cap
(not shown) for large object straining capacity can be
2128921.
-
selectively provided without changing any portion of thepump 28.
The preferred embodiment of the invention has been
set forth in the drawings and specifications, and
although specific terms are employed, these are used in a
5 generic or descriptive sense only and are not used for
purposes of limitation. Changes in the form and
proportion of parts as well as in the substitution of
equivalence are contemplated as circumstances may suggest
or render expedient without departing from the spirit or
scope of the invention as further defined in the
following claims.
/
